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External Anatomy
Sensory Organ for vision
-Situated in bony, orbital cavity for
– Eyelids= shades that add protection form injury,
strong light , dust
– Eyelashes= hairs to filter dust & dirt
Limbus – border b/t the cornea & sclera
 Palpebral fissures – elliptical open space b/t
 Canthus- corners of the eye where the lids
meet, inner & outer
 Caruncle – sm. Fleshy mass containing
sebaceous glands at inner canthus
Within the upper eyelid
Tarsal plates, connective tissue gives upper lid
Meibomian glands, in the plates, lubricate the
lids, stops overflow of tears, airtight seal
when lids closed
Exposed part of the eye
– Conjunctiva, folded envelope b/t eyelids &
thin mucous membrane, transparent protective
covering of the exposed part of the eye.
Palpebral conjunctiva lines the lids, is clear but has
sm .bld. Vessels
Bulbar conjunctiva is over eyeball, white sclera
show through, merges at limbus with cornea
Cornea – clear, covers & protects iris &
Lacrimal apparatus – irrigates conjunctiva
& cornea
3 parts
Lacrimal gland, upper, outer corner of eye = tears
Puncta= inner canthus, tear drainage
Nasolacrimal duct= allows tears to drain from
puncta to nasolacrimal sac. Tears then empty into
the inferior meatus of the nose
Extraoccular muscles
6 muscles
Attach eyeball to orbit
Straight and rotary movement
Four straight muscles
Superior rectus
Inferior rectus
Lateral rectus
Medial rectus
Two slanting/ oblique muscles
5. Superior
6. Inferior
Humans have a Binocular, single – image
visual system – Eyes normally move as a
Eye movement stimulated by Cranial
• III Oculomotor
• IV Trochlear
• VI Abducens
Internal Anatomy
The eye has 3 layers, the outer & inner
layer can be viewed using opthalmascope
Sclera (outer layer) tough, protective,
white covering connects with the  Cornea – transparent, protects pupil &
iris – helps focus light on retina
Middle layer
 Choroid – dark pigmentation to prevent internal
light reflection, supplies bld. to retina
 Pupil – PERRLA
 Lens – biconvex disc, transparent, thickness
controlled by ciliary body, bulges = near;
flattens = distant
 Anterior chamber – posterior to cornea,
anterior to iris & lens, has aqueous humor
supplies nutrients & drains wastes
Inner layer – Retina – visual receptive
layer – light waves changed to nerve
 Retinal structures
Optic disc – retinal fibers meet & form optic
nerve, nasal side of retina, creamy yellow orange
to pink, round or oval shape, physiologic cup
inside the disc for bld.vessels to enter & exit
Retina vessels – paired arteries & veins
Macula – temporal side of fundus, darker pigmented
region, surround the fovea centralis
 Fovea Centralis- area of sharpest & keenest vision,
Very sensitive to light
Visual Pathways & Fields
Objects reflect light
 Rays refracted by cornea, aqueous humor, lens,
vitreous body and onto retina.
 Light stimulus is changed to nerve impulses, travel
thru optic nerve to visual cortex in occipital lobe
 Image on retina is upside down & reversed. At the
optic chiasm retinal fibers cross over. Right side of
brain looks at left side of world.
Visual reflexes
Pupillary light reflex – bright light = constriction
– Direct light reflex
– Consensual light reflex
Fixation – ability to track an object & keep image
on the fovea, can be impaired by drugs, alcohol,
fatigue & inattention
 Accomodation – for near vision = pupil
constriction & convergence of eyes
Subjective data
Vision difficulty
 Pain
 Strabismus, diplopia
 Redness, swelling
 Watering, discharge
 Past history ocular problems
 Glaucoma
Glasses/ contacts
 Medications
 Vision loss- coping mechanisms
 Self–care behaviors
Objective data
The Physical Exam
– Position- sitting, head at eye level
– Snellen eye chart- visual acuity
– Handheld visual screener-near vision
– Opaque card
– Penlight
– Applicator stick
– Ophthalmoscope
Test visual acuity
Snellen eye chart
Stand 20 ft. from chart
Glasses / contacts (Document )
Remove eye wear, retest
Normal visual acuity is 20/20 – top # is distance
person is standing from the chart
20/30 refer to opthalmologist or
If unable to see largest letters, move to 10 feet –
record as 10/200
Test for near vision
Vision screener
 People > 40yrs or difficulty reading
 Test each eye with glasses
 Hold card 14in. from eyes
 Normal result 14 / 14
 Test using any available reading material if
no card available
Presbyopia is a normal physiological
change in near vision occurs with aging =
note if the person moves the card farther
Test visual fields
Confrontation test
Compares peripheral vision with a tester
who has normal peripheral vision
 2 ft. apart, eye level
 Tester & client cover opposite eyes
 Tester advances finger in the periphery
– Superiorly ( 50 degrees )
– Inferiorly ( 70 degrees )
– Temporally ( 90 degrees )
Inspect Extraoccular Muscle
Corneal light reflex
 Cover test
 Diagnostic positions test
– 6 Cardinal Positions of Gaze
Inspect Extraocular Muscle
Corneal Light Reflex ( The Hirschberg Test)
assesses parallel eye alignment
– Shine light toward person’s eyes
– Tell to stare directly ahead
– Hold light 12 in. away
– Light should reflect on both corneas in same
Cover Test- detects deviated alignment
– Stare straight at examiner’s nose
– Cover 1 eye of the person being examined with opaque
– Normally the uncovered eye should maintain a steady,
fixed gaze
– Covered eye- should stare straight ahead when covered
& then uncovered. If muscle weakness exists the
covered eye will relax and then jump to fixed position
when uncovered..
Diagnostic Positions Test
6 cardinal positions of gaze –
– Determines muscle weakness during movement
– Person must hold head steady
– Follow movement of object (examiner’s finger, pen etc)
only with eyes
– Hold object 12 in. from person
– Move thru each position, clockwise, hold , then back to
– Normal response= parallel tracking with both eyes
During this test be aware of Nystagmus-fine
jerky movement seen around the iris
 Mild nystagmus in extreme lateral gaze is
normal but not normal in any other position
Inspect External Structures
General – movement & facial expression
Eyebrows – 2(bilateral), symmetrical (look the
same; move the same)
Eyelids & Lashes – present, approximate when
closed, no redness, swelling, discharge, lesions?
Eyeballs- alignment, ? Protrusion? Sunken?
Conjunctiva & Sclera – moist, glossy, clear, white
Eversion of the upper eyelid FYI – we will
not do this examine in lab see pg. 312 for
technique – usually done for complaint of
eye pain due to foreign body
Lacrimal Apparatus
– Person looks down
– Using thumbs, slide outer part of upper lid
along bony orbit
– Note redness or swelling
– Press index finger against lacrimal sac at inner
– Normal response is slight eversion of lower lid,
no tearing or discharge
Anterior Eyeball Structures
Cornea & lens
 Iris & pupil
– Size & shape
– Pupillary light reflex
– Accommodation
Cornea & Lens
Shine light from side across cornea
 Check smoothness, clarity
 Normally no opacities
Iris and Pupil
Iris = flat, round, regular, even color
 Pupils = PERRLA
– Resting size norm = 3-5mm
– 5% population have pupils of 2 diff. Sizes
called Anisocoria
Pupillary Light Reflex
– Darken room
– Person gazes straight ahead
– Advance light from the side
 Direct light reflex
 Consensual light reflex
– Measure pupil size before & after light reflex
– Measurement R3/1 L3/1 =both pupils measure
3mm in resting state & 1mm with light
– focus on distant object -dilatation of pupils
– Shift gaze to near object – pupils constrict &
Record the normal response to these tests as
PERRLA = Pupils Equal, Round, React
to Light and Accomodation
Ocular Fundus (internal
surface of retina)
Use Opthalmoscope- try keeping both eyes
open- practice looking at a ring on your
finger. Become familiar with the instrument
before you examine your partner’s eyes
Diopter of opthalmoscope
– Black numbers = +diopter, focus on near
– Red numbers = - diopter, focus on further
Use ophthalmoscope in darkened room =
dilates pupils
Remove examiner’s and person’s eyeglasses
but contact lenses may be left in.
 Select lg. White aperture light
 Person should focus on a distant object and
try & remain still
 Examiner hold ophthalmoscope in Right
hand to right eye to eamine person’s right
Begin 10in away at 150 lateral angle &
 Keep sight of red reflex
 Adjust lens to +6 as you advance till your
foreheads almost touch. Adjust diopter to
– Normal vision set at 0. Nearsighted use red #s.
Farsighted use black.
Retinal background
Light – dark red normally
 Note Lesions
– Size, shape, color, distribution
Macula & Fovea Centralis
Last in Funduscopic exam
– 1 DD in size
– Darker than rest of fundus
– Foveal light reflex
– Exam last
Retinal Vessels
Light red
Dark red
Smaller 2/3 to
4/5 diam. Of
Read Aging & Developmental
Review Abnormalities of the Eyes
3 most common causes of
decreased visual functioning in
the older adult
Cataract (lens opacity)
 Glaucoma (increased ocular pressure) = loss
of peripheral vision
 Macular degeneration (breakdown of cells
in the macula lutea) = loss of central vision